#include<iostream>
#include<vector>
#include<algorithm>

using namespace std;

int main(){
	vector<int> amount(3);
	cin>>amount[0]>>amount[1]>>amount[2];
	
	sort(amount.begin(), amount.end());
    if (amount[0] + amount[1] <= amount[2]) cout<<amount[2];
    else {
        int t = amount[0] + amount[1] - amount[2];
        cout<<(t + 1) / 2 + amount[2];
    }

    return 0;
} 
